lib/el3_runtime/aarch64/context.S - filogic/atf - Gitiles

 /*
  * Copyright (c) 2013-2023, Arm Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */

 #include <arch.h>
 #include <asm_macros.S>
 #include <assert_macros.S>
 #include <context.h>
 #include <el3_common_macros.S>

 	.global	el1_sysregs_context_save
 	.global	el1_sysregs_context_restore
 #if CTX_INCLUDE_FPREGS
 	.global	fpregs_context_save
 	.global	fpregs_context_restore
 #endif /* CTX_INCLUDE_FPREGS */
 	.global	prepare_el3_entry
 	.global	restore_gp_pmcr_pauth_regs
 	.global save_and_update_ptw_el1_sys_regs
 	.global	el3_exit


 /* ------------------------------------------------------------------
  * The following function strictly follows the AArch64 PCS to use
  * x9-x17 (temporary caller-saved registers) to save EL1 system
  * register context. It assumes that 'x0' is pointing to a
  * 'el1_sys_regs' structure where the register context will be saved.
  * ------------------------------------------------------------------
  */
 func el1_sysregs_context_save

 	mrs	x9, spsr_el1
 	mrs	x10, elr_el1
 	stp	x9, x10, [x0, #CTX_SPSR_EL1]

 #if !ERRATA_SPECULATIVE_AT
 	mrs	x15, sctlr_el1
 	mrs	x16, tcr_el1
 	stp	x15, x16, [x0, #CTX_SCTLR_EL1]
 #endif /* ERRATA_SPECULATIVE_AT */

 	mrs	x17, cpacr_el1
 	mrs	x9, csselr_el1
 	stp	x17, x9, [x0, #CTX_CPACR_EL1]

 	mrs	x10, sp_el1
 	mrs	x11, esr_el1
 	stp	x10, x11, [x0, #CTX_SP_EL1]

 	mrs	x12, ttbr0_el1
 	mrs	x13, ttbr1_el1
 	stp	x12, x13, [x0, #CTX_TTBR0_EL1]

 	mrs	x14, mair_el1
 	mrs	x15, amair_el1
 	stp	x14, x15, [x0, #CTX_MAIR_EL1]

 	mrs	x16, actlr_el1
 	mrs	x17, tpidr_el1
 	stp	x16, x17, [x0, #CTX_ACTLR_EL1]

 	mrs	x9, tpidr_el0
 	mrs	x10, tpidrro_el0
 	stp	x9, x10, [x0, #CTX_TPIDR_EL0]

 	mrs	x13, par_el1
 	mrs	x14, far_el1
 	stp	x13, x14, [x0, #CTX_PAR_EL1]

 	mrs	x15, afsr0_el1
 	mrs	x16, afsr1_el1
 	stp	x15, x16, [x0, #CTX_AFSR0_EL1]

 	mrs	x17, contextidr_el1
 	mrs	x9, vbar_el1
 	stp	x17, x9, [x0, #CTX_CONTEXTIDR_EL1]

 	/* Save AArch32 system registers if the build has instructed so */
 #if CTX_INCLUDE_AARCH32_REGS
 	mrs	x11, spsr_abt
 	mrs	x12, spsr_und
 	stp	x11, x12, [x0, #CTX_SPSR_ABT]

 	mrs	x13, spsr_irq
 	mrs	x14, spsr_fiq
 	stp	x13, x14, [x0, #CTX_SPSR_IRQ]

 	mrs	x15, dacr32_el2
 	mrs	x16, ifsr32_el2
 	stp	x15, x16, [x0, #CTX_DACR32_EL2]
 #endif /* CTX_INCLUDE_AARCH32_REGS */

 	/* Save NS timer registers if the build has instructed so */
 #if NS_TIMER_SWITCH
 	mrs	x10, cntp_ctl_el0
 	mrs	x11, cntp_cval_el0
 	stp	x10, x11, [x0, #CTX_CNTP_CTL_EL0]

 	mrs	x12, cntv_ctl_el0
 	mrs	x13, cntv_cval_el0
 	stp	x12, x13, [x0, #CTX_CNTV_CTL_EL0]

 	mrs	x14, cntkctl_el1
 	str	x14, [x0, #CTX_CNTKCTL_EL1]
 #endif /* NS_TIMER_SWITCH */

 	/* Save MTE system registers if the build has instructed so */
 #if CTX_INCLUDE_MTE_REGS
 	mrs	x15, TFSRE0_EL1
 	mrs	x16, TFSR_EL1
 	stp	x15, x16, [x0, #CTX_TFSRE0_EL1]

 	mrs	x9, RGSR_EL1
 	mrs	x10, GCR_EL1
 	stp	x9, x10, [x0, #CTX_RGSR_EL1]
 #endif /* CTX_INCLUDE_MTE_REGS */

 	ret
 endfunc el1_sysregs_context_save

 /* ------------------------------------------------------------------
  * The following function strictly follows the AArch64 PCS to use
  * x9-x17 (temporary caller-saved registers) to restore EL1 system
  * register context.  It assumes that 'x0' is pointing to a
  * 'el1_sys_regs' structure from where the register context will be
  * restored
  * ------------------------------------------------------------------
  */
 func el1_sysregs_context_restore

 	ldp	x9, x10, [x0, #CTX_SPSR_EL1]
 	msr	spsr_el1, x9
 	msr	elr_el1, x10

 #if !ERRATA_SPECULATIVE_AT
 	ldp	x15, x16, [x0, #CTX_SCTLR_EL1]
 	msr	sctlr_el1, x15
 	msr	tcr_el1, x16
 #endif /* ERRATA_SPECULATIVE_AT */

 	ldp	x17, x9, [x0, #CTX_CPACR_EL1]
 	msr	cpacr_el1, x17
 	msr	csselr_el1, x9

 	ldp	x10, x11, [x0, #CTX_SP_EL1]
 	msr	sp_el1, x10
 	msr	esr_el1, x11

 	ldp	x12, x13, [x0, #CTX_TTBR0_EL1]
 	msr	ttbr0_el1, x12
 	msr	ttbr1_el1, x13

 	ldp	x14, x15, [x0, #CTX_MAIR_EL1]
 	msr	mair_el1, x14
 	msr	amair_el1, x15

 	ldp 	x16, x17, [x0, #CTX_ACTLR_EL1]
 	msr	actlr_el1, x16
 	msr	tpidr_el1, x17

 	ldp	x9, x10, [x0, #CTX_TPIDR_EL0]
 	msr	tpidr_el0, x9
 	msr	tpidrro_el0, x10

 	ldp	x13, x14, [x0, #CTX_PAR_EL1]
 	msr	par_el1, x13
 	msr	far_el1, x14

 	ldp	x15, x16, [x0, #CTX_AFSR0_EL1]
 	msr	afsr0_el1, x15
 	msr	afsr1_el1, x16

 	ldp	x17, x9, [x0, #CTX_CONTEXTIDR_EL1]
 	msr	contextidr_el1, x17
 	msr	vbar_el1, x9

 	/* Restore AArch32 system registers if the build has instructed so */
 #if CTX_INCLUDE_AARCH32_REGS
 	ldp	x11, x12, [x0, #CTX_SPSR_ABT]
 	msr	spsr_abt, x11
 	msr	spsr_und, x12

 	ldp	x13, x14, [x0, #CTX_SPSR_IRQ]
 	msr	spsr_irq, x13
 	msr	spsr_fiq, x14

 	ldp	x15, x16, [x0, #CTX_DACR32_EL2]
 	msr	dacr32_el2, x15
 	msr	ifsr32_el2, x16
 #endif /* CTX_INCLUDE_AARCH32_REGS */

 	/* Restore NS timer registers if the build has instructed so */
 #if NS_TIMER_SWITCH
 	ldp	x10, x11, [x0, #CTX_CNTP_CTL_EL0]
 	msr	cntp_ctl_el0, x10
 	msr	cntp_cval_el0, x11

 	ldp	x12, x13, [x0, #CTX_CNTV_CTL_EL0]
 	msr	cntv_ctl_el0, x12
 	msr	cntv_cval_el0, x13

 	ldr	x14, [x0, #CTX_CNTKCTL_EL1]
 	msr	cntkctl_el1, x14
 #endif /* NS_TIMER_SWITCH */

 	/* Restore MTE system registers if the build has instructed so */
 #if CTX_INCLUDE_MTE_REGS
 	ldp	x11, x12, [x0, #CTX_TFSRE0_EL1]
 	msr	TFSRE0_EL1, x11
 	msr	TFSR_EL1, x12

 	ldp	x13, x14, [x0, #CTX_RGSR_EL1]
 	msr	RGSR_EL1, x13
 	msr	GCR_EL1, x14
 #endif /* CTX_INCLUDE_MTE_REGS */

 	/* No explict ISB required here as ERET covers it */
 	ret
 endfunc el1_sysregs_context_restore

 /* ------------------------------------------------------------------
  * The following function follows the aapcs_64 strictly to use
  * x9-x17 (temporary caller-saved registers according to AArch64 PCS)
  * to save floating point register context. It assumes that 'x0' is
  * pointing to a 'fp_regs' structure where the register context will
  * be saved.
  *
  * Access to VFP registers will trap if CPTR_EL3.TFP is set.
  * However currently we don't use VFP registers nor set traps in
  * Trusted Firmware, and assume it's cleared.
  *
  * TODO: Revisit when VFP is used in secure world
  * ------------------------------------------------------------------
  */
 #if CTX_INCLUDE_FPREGS
 func fpregs_context_save
 	stp	q0, q1, [x0, #CTX_FP_Q0]
 	stp	q2, q3, [x0, #CTX_FP_Q2]
 	stp	q4, q5, [x0, #CTX_FP_Q4]
 	stp	q6, q7, [x0, #CTX_FP_Q6]
 	stp	q8, q9, [x0, #CTX_FP_Q8]
 	stp	q10, q11, [x0, #CTX_FP_Q10]
 	stp	q12, q13, [x0, #CTX_FP_Q12]
 	stp	q14, q15, [x0, #CTX_FP_Q14]
 	stp	q16, q17, [x0, #CTX_FP_Q16]
 	stp	q18, q19, [x0, #CTX_FP_Q18]
 	stp	q20, q21, [x0, #CTX_FP_Q20]
 	stp	q22, q23, [x0, #CTX_FP_Q22]
 	stp	q24, q25, [x0, #CTX_FP_Q24]
 	stp	q26, q27, [x0, #CTX_FP_Q26]
 	stp	q28, q29, [x0, #CTX_FP_Q28]
 	stp	q30, q31, [x0, #CTX_FP_Q30]

 	mrs	x9, fpsr
 	str	x9, [x0, #CTX_FP_FPSR]

 	mrs	x10, fpcr
 	str	x10, [x0, #CTX_FP_FPCR]

 #if CTX_INCLUDE_AARCH32_REGS
 	mrs	x11, fpexc32_el2
 	str	x11, [x0, #CTX_FP_FPEXC32_EL2]
 #endif /* CTX_INCLUDE_AARCH32_REGS */
 	ret
 endfunc fpregs_context_save

 /* ------------------------------------------------------------------
  * The following function follows the aapcs_64 strictly to use x9-x17
  * (temporary caller-saved registers according to AArch64 PCS) to
  * restore floating point register context. It assumes that 'x0' is
  * pointing to a 'fp_regs' structure from where the register context
  * will be restored.
  *
  * Access to VFP registers will trap if CPTR_EL3.TFP is set.
  * However currently we don't use VFP registers nor set traps in
  * Trusted Firmware, and assume it's cleared.
  *
  * TODO: Revisit when VFP is used in secure world
  * ------------------------------------------------------------------
  */
 func fpregs_context_restore
 	ldp	q0, q1, [x0, #CTX_FP_Q0]
 	ldp	q2, q3, [x0, #CTX_FP_Q2]
 	ldp	q4, q5, [x0, #CTX_FP_Q4]
 	ldp	q6, q7, [x0, #CTX_FP_Q6]
 	ldp	q8, q9, [x0, #CTX_FP_Q8]
 	ldp	q10, q11, [x0, #CTX_FP_Q10]
 	ldp	q12, q13, [x0, #CTX_FP_Q12]
 	ldp	q14, q15, [x0, #CTX_FP_Q14]
 	ldp	q16, q17, [x0, #CTX_FP_Q16]
 	ldp	q18, q19, [x0, #CTX_FP_Q18]
 	ldp	q20, q21, [x0, #CTX_FP_Q20]
 	ldp	q22, q23, [x0, #CTX_FP_Q22]
 	ldp	q24, q25, [x0, #CTX_FP_Q24]
 	ldp	q26, q27, [x0, #CTX_FP_Q26]
 	ldp	q28, q29, [x0, #CTX_FP_Q28]
 	ldp	q30, q31, [x0, #CTX_FP_Q30]

 	ldr	x9, [x0, #CTX_FP_FPSR]
 	msr	fpsr, x9

 	ldr	x10, [x0, #CTX_FP_FPCR]
 	msr	fpcr, x10

 #if CTX_INCLUDE_AARCH32_REGS
 	ldr	x11, [x0, #CTX_FP_FPEXC32_EL2]
 	msr	fpexc32_el2, x11
 #endif /* CTX_INCLUDE_AARCH32_REGS */

 	/*
 	 * No explict ISB required here as ERET to
 	 * switch to secure EL1 or non-secure world
 	 * covers it
 	 */

 	ret
 endfunc fpregs_context_restore
 #endif /* CTX_INCLUDE_FPREGS */

 	/*
 	 * Set SCR_EL3.EA bit to enable SErrors at EL3
 	 */
 	.macro enable_serror_at_el3
 	mrs     x8, scr_el3
 	orr     x8, x8, #SCR_EA_BIT
 	msr     scr_el3, x8
 	.endm

 	/*
 	 * Set the PSTATE bits not set when the exception was taken as
 	 * described in the AArch64.TakeException() pseudocode function
 	 * in ARM DDI 0487F.c page J1-7635 to a default value.
 	 */
 	.macro set_unset_pstate_bits
 	/*
 	 * If Data Independent Timing (DIT) functionality is implemented,
 	 * always enable DIT in EL3
 	 */
 #if ENABLE_FEAT_DIT
 #if ENABLE_FEAT_DIT == 2
 	mrs	x8, id_aa64pfr0_el1
 	and	x8, x8, #(ID_AA64PFR0_DIT_MASK << ID_AA64PFR0_DIT_SHIFT)
 	cbz	x8, 1f
 #endif
 	mov     x8, #DIT_BIT
 	msr     DIT, x8
 1:
 #endif /* ENABLE_FEAT_DIT */
 	.endm /* set_unset_pstate_bits */

 /*-------------------------------------------------------------------------
  * This macro checks the ENABLE_FEAT_MPAM state, performs ID register
  * check to see if the platform supports MPAM extension and restores MPAM3
  * register value if it is FEAT_STATE_ENABLED/FEAT_STATE_CHECKED.
  *
  * This is particularly more complicated because we can't check
  * if the platform supports MPAM  by looking for status of a particular bit
  * in the MDCR_EL3 or CPTR_EL3 register like other extensions.
  * ------------------------------------------------------------------------
  */

 	.macro	restore_mpam3_el3
 #if ENABLE_FEAT_MPAM
 #if ENABLE_FEAT_MPAM == 2

 	mrs x8, id_aa64pfr0_el1
 	lsr x8, x8, #(ID_AA64PFR0_MPAM_SHIFT)
 	and x8, x8, #(ID_AA64PFR0_MPAM_MASK)
 	mrs x7, id_aa64pfr1_el1
 	lsr x7, x7, #(ID_AA64PFR1_MPAM_FRAC_SHIFT)
 	and x7, x7, #(ID_AA64PFR1_MPAM_FRAC_MASK)
 	orr x7, x7, x8
 	cbz x7, no_mpam
 #endif
 	/* -----------------------------------------------------------
 	 * Restore MPAM3_EL3 register as per context state
 	 * Currently we only enable MPAM for NS world and trap to EL3
 	 * for MPAM access in lower ELs of Secure and Realm world
 	 * x9 holds address of the per_world context
 	 * -----------------------------------------------------------
 	 */

 	ldr	x17, [x9, #CTX_MPAM3_EL3]
 	msr	S3_6_C10_C5_0, x17 /* mpam3_el3 */

 no_mpam:
 #endif
 	.endm /* restore_mpam3_el3 */

 /* ------------------------------------------------------------------
  * The following macro is used to save and restore all the general
  * purpose and ARMv8.3-PAuth (if enabled) registers.
  * It also checks if the Secure Cycle Counter (PMCCNTR_EL0)
  * is disabled in EL3/Secure (ARMv8.5-PMU), wherein PMCCNTR_EL0
  * needs not to be saved/restored during world switch.
  *
  * Ideally we would only save and restore the callee saved registers
  * when a world switch occurs but that type of implementation is more
  * complex. So currently we will always save and restore these
  * registers on entry and exit of EL3.
  * clobbers: x18
  * ------------------------------------------------------------------
  */
 	.macro save_gp_pmcr_pauth_regs
 	stp	x0, x1, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X0]
 	stp	x2, x3, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X2]
 	stp	x4, x5, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X4]
 	stp	x6, x7, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X6]
 	stp	x8, x9, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X8]
 	stp	x10, x11, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X10]
 	stp	x12, x13, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X12]
 	stp	x14, x15, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X14]
 	stp	x16, x17, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X16]
 	stp	x18, x19, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X18]
 	stp	x20, x21, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X20]
 	stp	x22, x23, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X22]
 	stp	x24, x25, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X24]
 	stp	x26, x27, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X26]
 	stp	x28, x29, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X28]
 	mrs	x18, sp_el0
 	str	x18, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_SP_EL0]

 	/* PMUv3 is presumed to be always present */
 	mrs	x9, pmcr_el0
 	str	x9, [sp, #CTX_EL3STATE_OFFSET + CTX_PMCR_EL0]
 	/* Disable cycle counter when event counting is prohibited */
 	orr	x9, x9, #PMCR_EL0_DP_BIT
 	msr	pmcr_el0, x9
 	isb
 #if CTX_INCLUDE_PAUTH_REGS
 	/* ----------------------------------------------------------
  	 * Save the ARMv8.3-PAuth keys as they are not banked
  	 * by exception level
 	 * ----------------------------------------------------------
 	 */
 	add	x19, sp, #CTX_PAUTH_REGS_OFFSET

 	mrs	x20, APIAKeyLo_EL1	/* x21:x20 = APIAKey */
 	mrs	x21, APIAKeyHi_EL1
 	mrs	x22, APIBKeyLo_EL1	/* x23:x22 = APIBKey */
 	mrs	x23, APIBKeyHi_EL1
 	mrs	x24, APDAKeyLo_EL1	/* x25:x24 = APDAKey */
 	mrs	x25, APDAKeyHi_EL1
 	mrs	x26, APDBKeyLo_EL1	/* x27:x26 = APDBKey */
 	mrs	x27, APDBKeyHi_EL1
 	mrs	x28, APGAKeyLo_EL1	/* x29:x28 = APGAKey */
 	mrs	x29, APGAKeyHi_EL1

 	stp	x20, x21, [x19, #CTX_PACIAKEY_LO]
 	stp	x22, x23, [x19, #CTX_PACIBKEY_LO]
 	stp	x24, x25, [x19, #CTX_PACDAKEY_LO]
 	stp	x26, x27, [x19, #CTX_PACDBKEY_LO]
 	stp	x28, x29, [x19, #CTX_PACGAKEY_LO]
 #endif /* CTX_INCLUDE_PAUTH_REGS */
 	.endm /* save_gp_pmcr_pauth_regs */

 /* -----------------------------------------------------------------
  * This function saves the context and sets the PSTATE to a known
  * state, preparing entry to el3.
  * Save all the general purpose and ARMv8.3-PAuth (if enabled)
  * registers.
  * Then set any of the PSTATE bits that are not set by hardware
  * according to the Aarch64.TakeException pseudocode in the Arm
  * Architecture Reference Manual to a default value for EL3.
  * clobbers: x17
  * -----------------------------------------------------------------
  */
 func prepare_el3_entry
 	save_gp_pmcr_pauth_regs
 	enable_serror_at_el3
 	/*
 	 * Set the PSTATE bits not described in the Aarch64.TakeException
 	 * pseudocode to their default values.
 	 */
 	set_unset_pstate_bits
 	ret
 endfunc prepare_el3_entry

 /* ------------------------------------------------------------------
  * This function restores ARMv8.3-PAuth (if enabled) and all general
  * purpose registers except x30 from the CPU context.
  * x30 register must be explicitly restored by the caller.
  * ------------------------------------------------------------------
  */
 func restore_gp_pmcr_pauth_regs
 #if CTX_INCLUDE_PAUTH_REGS
  	/* Restore the ARMv8.3 PAuth keys */
 	add	x10, sp, #CTX_PAUTH_REGS_OFFSET

 	ldp	x0, x1, [x10, #CTX_PACIAKEY_LO]	/* x1:x0 = APIAKey */
 	ldp	x2, x3, [x10, #CTX_PACIBKEY_LO]	/* x3:x2 = APIBKey */
 	ldp	x4, x5, [x10, #CTX_PACDAKEY_LO]	/* x5:x4 = APDAKey */
 	ldp	x6, x7, [x10, #CTX_PACDBKEY_LO]	/* x7:x6 = APDBKey */
 	ldp	x8, x9, [x10, #CTX_PACGAKEY_LO]	/* x9:x8 = APGAKey */

 	msr	APIAKeyLo_EL1, x0
 	msr	APIAKeyHi_EL1, x1
 	msr	APIBKeyLo_EL1, x2
 	msr	APIBKeyHi_EL1, x3
 	msr	APDAKeyLo_EL1, x4
 	msr	APDAKeyHi_EL1, x5
 	msr	APDBKeyLo_EL1, x6
 	msr	APDBKeyHi_EL1, x7
 	msr	APGAKeyLo_EL1, x8
 	msr	APGAKeyHi_EL1, x9
 #endif /* CTX_INCLUDE_PAUTH_REGS */

 	/* PMUv3 is presumed to be always present */
 	ldr	x0, [sp, #CTX_EL3STATE_OFFSET + CTX_PMCR_EL0]
 	msr	pmcr_el0, x0
 	ldp	x0, x1, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X0]
 	ldp	x2, x3, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X2]
 	ldp	x4, x5, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X4]
 	ldp	x6, x7, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X6]
 	ldp	x8, x9, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X8]
 	ldp	x10, x11, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X10]
 	ldp	x12, x13, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X12]
 	ldp	x14, x15, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X14]
 	ldp	x16, x17, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X16]
 	ldp	x18, x19, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X18]
 	ldp	x20, x21, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X20]
 	ldp	x22, x23, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X22]
 	ldp	x24, x25, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X24]
 	ldp	x26, x27, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X26]
 	ldr	x28, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_SP_EL0]
 	msr	sp_el0, x28
 	ldp	x28, x29, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X28]
 	ret
 endfunc restore_gp_pmcr_pauth_regs

 /*
  * In case of ERRATA_SPECULATIVE_AT, save SCTLR_EL1 and TCR_EL1
  * registers and update EL1 registers to disable stage1 and stage2
  * page table walk
  */
 func save_and_update_ptw_el1_sys_regs
 	/* ----------------------------------------------------------
 	 * Save only sctlr_el1 and tcr_el1 registers
 	 * ----------------------------------------------------------
 	 */
 	mrs	x29, sctlr_el1
 	str	x29, [sp, #(CTX_EL1_SYSREGS_OFFSET + CTX_SCTLR_EL1)]
 	mrs	x29, tcr_el1
 	str	x29, [sp, #(CTX_EL1_SYSREGS_OFFSET + CTX_TCR_EL1)]

 	/* ------------------------------------------------------------
 	 * Must follow below order in order to disable page table
 	 * walk for lower ELs (EL1 and EL0). First step ensures that
 	 * page table walk is disabled for stage1 and second step
 	 * ensures that page table walker should use TCR_EL1.EPDx
 	 * bits to perform address translation. ISB ensures that CPU
 	 * does these 2 steps in order.
 	 *
 	 * 1. Update TCR_EL1.EPDx bits to disable page table walk by
 	 *    stage1.
 	 * 2. Enable MMU bit to avoid identity mapping via stage2
 	 *    and force TCR_EL1.EPDx to be used by the page table
 	 *    walker.
 	 * ------------------------------------------------------------
 	 */
 	orr	x29, x29, #(TCR_EPD0_BIT)
 	orr	x29, x29, #(TCR_EPD1_BIT)
 	msr	tcr_el1, x29
 	isb
 	mrs	x29, sctlr_el1
 	orr	x29, x29, #SCTLR_M_BIT
 	msr	sctlr_el1, x29
 	isb

 	ret
 endfunc save_and_update_ptw_el1_sys_regs

 /* -----------------------------------------------------------------
 * The below macro returns the address of the per_world context for
 * the security state, retrieved through "get_security_state" macro.
 * The per_world context address is returned in the register argument.
 * Clobbers: x9, x10
 * ------------------------------------------------------------------
 */

 .macro get_per_world_context _reg:req
 	ldr 	x10, [sp, #CTX_EL3STATE_OFFSET + CTX_SCR_EL3]
 	get_security_state x9, x10
 	mov_imm	x10, (CTX_PERWORLD_EL3STATE_END - CTX_CPTR_EL3)
 	mul	x9, x9, x10
 	adrp	x10, per_world_context
 	add	x10, x10, :lo12:per_world_context
 	add	x9, x9, x10
 	mov 	\_reg, x9
 .endm

 /* ------------------------------------------------------------------
  * This routine assumes that the SP_EL3 is pointing to a valid
  * context structure from where the gp regs and other special
  * registers can be retrieved.
  * ------------------------------------------------------------------
  */
 func el3_exit
 #if ENABLE_ASSERTIONS
 	/* el3_exit assumes SP_EL0 on entry */
 	mrs	x17, spsel
 	cmp	x17, #MODE_SP_EL0
 	ASM_ASSERT(eq)
 #endif /* ENABLE_ASSERTIONS */

 	/* ----------------------------------------------------------
 	 * Save the current SP_EL0 i.e. the EL3 runtime stack which
 	 * will be used for handling the next SMC.
 	 * Then switch to SP_EL3.
 	 * ----------------------------------------------------------
 	 */
 	mov	x17, sp
 	msr	spsel, #MODE_SP_ELX
 	str	x17, [sp, #CTX_EL3STATE_OFFSET + CTX_RUNTIME_SP]

 	/* ----------------------------------------------------------
 	 * Restore CPTR_EL3.
 	 * ZCR is only restored if SVE is supported and enabled.
 	 * Synchronization is required before zcr_el3 is addressed.
 	 * ----------------------------------------------------------
 	 */

 	/* The address of the per_world context is stored in x9 */
 	get_per_world_context x9

 	ldp	x19, x20, [x9, #CTX_CPTR_EL3]
 	msr	cptr_el3, x19

 #if IMAGE_BL31
 	ands	x19, x19, #CPTR_EZ_BIT
 	beq	sve_not_enabled

 	isb
 	msr	S3_6_C1_C2_0, x20 /* zcr_el3 */
 sve_not_enabled:

 	restore_mpam3_el3

 #endif /* IMAGE_BL31 */

 #if IMAGE_BL31 && DYNAMIC_WORKAROUND_CVE_2018_3639
 	/* ----------------------------------------------------------
 	 * Restore mitigation state as it was on entry to EL3
 	 * ----------------------------------------------------------
 	 */
 	ldr	x17, [sp, #CTX_CVE_2018_3639_OFFSET + CTX_CVE_2018_3639_DISABLE]
 	cbz	x17, 1f
 	blr	x17
 1:
 #endif /* IMAGE_BL31 && DYNAMIC_WORKAROUND_CVE_2018_3639 */

 #if IMAGE_BL31
 	synchronize_errors
 #endif /* IMAGE_BL31 */

 	/* ----------------------------------------------------------
 	 * Restore SPSR_EL3, ELR_EL3 and SCR_EL3 prior to ERET
 	 * ----------------------------------------------------------
 	 */
 	ldr	x18, [sp, #CTX_EL3STATE_OFFSET + CTX_SCR_EL3]
 	ldp	x16, x17, [sp, #CTX_EL3STATE_OFFSET + CTX_SPSR_EL3]
 	msr	scr_el3, x18
 	msr	spsr_el3, x16
 	msr	elr_el3, x17

 	restore_ptw_el1_sys_regs

 	/* ----------------------------------------------------------
 	 * Restore general purpose (including x30), PMCR_EL0 and
 	 * ARMv8.3-PAuth registers.
 	 * Exit EL3 via ERET to a lower exception level.
  	 * ----------------------------------------------------------
  	 */
 	bl	restore_gp_pmcr_pauth_regs
 	ldr	x30, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_LR]

 #ifdef IMAGE_BL31
 	/* Clear the EL3 flag as we are exiting el3 */
 	str	xzr, [sp, #CTX_EL3STATE_OFFSET + CTX_NESTED_EA_FLAG]
 #endif /* IMAGE_BL31 */

 	exception_return

 endfunc el3_exit
	/*
	* Copyright (c) 2013-2023, Arm Limited and Contributors. All rights reserved.
	*
	* SPDX-License-Identifier: BSD-3-Clause
	*/

	#include <arch.h>
	#include <asm_macros.S>
	#include <assert_macros.S>
	#include <context.h>
	#include <el3_common_macros.S>

	.global el1_sysregs_context_save
	.global el1_sysregs_context_restore
	#if CTX_INCLUDE_FPREGS
	.global fpregs_context_save
	.global fpregs_context_restore
	#endif /* CTX_INCLUDE_FPREGS */
	.global prepare_el3_entry
	.global restore_gp_pmcr_pauth_regs
	.global save_and_update_ptw_el1_sys_regs
	.global el3_exit


	/* ------------------------------------------------------------------
	* The following function strictly follows the AArch64 PCS to use
	* x9-x17 (temporary caller-saved registers) to save EL1 system
	* register context. It assumes that 'x0' is pointing to a
	* 'el1_sys_regs' structure where the register context will be saved.
	* ------------------------------------------------------------------
	*/
	func el1_sysregs_context_save

	mrs x9, spsr_el1
	mrs x10, elr_el1
	stp x9, x10, [x0, #CTX_SPSR_EL1]

	#if !ERRATA_SPECULATIVE_AT
	mrs x15, sctlr_el1
	mrs x16, tcr_el1
	stp x15, x16, [x0, #CTX_SCTLR_EL1]
	#endif /* ERRATA_SPECULATIVE_AT */

	mrs x17, cpacr_el1
	mrs x9, csselr_el1
	stp x17, x9, [x0, #CTX_CPACR_EL1]

	mrs x10, sp_el1
	mrs x11, esr_el1
	stp x10, x11, [x0, #CTX_SP_EL1]

	mrs x12, ttbr0_el1
	mrs x13, ttbr1_el1
	stp x12, x13, [x0, #CTX_TTBR0_EL1]

	mrs x14, mair_el1
	mrs x15, amair_el1
	stp x14, x15, [x0, #CTX_MAIR_EL1]

	mrs x16, actlr_el1
	mrs x17, tpidr_el1
	stp x16, x17, [x0, #CTX_ACTLR_EL1]

	mrs x9, tpidr_el0
	mrs x10, tpidrro_el0
	stp x9, x10, [x0, #CTX_TPIDR_EL0]

	mrs x13, par_el1
	mrs x14, far_el1
	stp x13, x14, [x0, #CTX_PAR_EL1]

	mrs x15, afsr0_el1
	mrs x16, afsr1_el1
	stp x15, x16, [x0, #CTX_AFSR0_EL1]

	mrs x17, contextidr_el1
	mrs x9, vbar_el1
	stp x17, x9, [x0, #CTX_CONTEXTIDR_EL1]

	/* Save AArch32 system registers if the build has instructed so */
	#if CTX_INCLUDE_AARCH32_REGS
	mrs x11, spsr_abt
	mrs x12, spsr_und
	stp x11, x12, [x0, #CTX_SPSR_ABT]

	mrs x13, spsr_irq
	mrs x14, spsr_fiq
	stp x13, x14, [x0, #CTX_SPSR_IRQ]

	mrs x15, dacr32_el2
	mrs x16, ifsr32_el2
	stp x15, x16, [x0, #CTX_DACR32_EL2]
	#endif /* CTX_INCLUDE_AARCH32_REGS */

	/* Save NS timer registers if the build has instructed so */
	#if NS_TIMER_SWITCH
	mrs x10, cntp_ctl_el0
	mrs x11, cntp_cval_el0
	stp x10, x11, [x0, #CTX_CNTP_CTL_EL0]

	mrs x12, cntv_ctl_el0
	mrs x13, cntv_cval_el0
	stp x12, x13, [x0, #CTX_CNTV_CTL_EL0]

	mrs x14, cntkctl_el1
	str x14, [x0, #CTX_CNTKCTL_EL1]
	#endif /* NS_TIMER_SWITCH */

	/* Save MTE system registers if the build has instructed so */
	#if CTX_INCLUDE_MTE_REGS
	mrs x15, TFSRE0_EL1
	mrs x16, TFSR_EL1
	stp x15, x16, [x0, #CTX_TFSRE0_EL1]

	mrs x9, RGSR_EL1
	mrs x10, GCR_EL1
	stp x9, x10, [x0, #CTX_RGSR_EL1]
	#endif /* CTX_INCLUDE_MTE_REGS */

	ret
	endfunc el1_sysregs_context_save

	/* ------------------------------------------------------------------
	* The following function strictly follows the AArch64 PCS to use
	* x9-x17 (temporary caller-saved registers) to restore EL1 system
	* register context. It assumes that 'x0' is pointing to a
	* 'el1_sys_regs' structure from where the register context will be
	* restored
	* ------------------------------------------------------------------
	*/
	func el1_sysregs_context_restore

	ldp x9, x10, [x0, #CTX_SPSR_EL1]
	msr spsr_el1, x9
	msr elr_el1, x10

	#if !ERRATA_SPECULATIVE_AT
	ldp x15, x16, [x0, #CTX_SCTLR_EL1]
	msr sctlr_el1, x15
	msr tcr_el1, x16
	#endif /* ERRATA_SPECULATIVE_AT */

	ldp x17, x9, [x0, #CTX_CPACR_EL1]
	msr cpacr_el1, x17
	msr csselr_el1, x9

	ldp x10, x11, [x0, #CTX_SP_EL1]
	msr sp_el1, x10
	msr esr_el1, x11

	ldp x12, x13, [x0, #CTX_TTBR0_EL1]
	msr ttbr0_el1, x12
	msr ttbr1_el1, x13

	ldp x14, x15, [x0, #CTX_MAIR_EL1]
	msr mair_el1, x14
	msr amair_el1, x15

	ldp x16, x17, [x0, #CTX_ACTLR_EL1]
	msr actlr_el1, x16
	msr tpidr_el1, x17

	ldp x9, x10, [x0, #CTX_TPIDR_EL0]
	msr tpidr_el0, x9
	msr tpidrro_el0, x10

	ldp x13, x14, [x0, #CTX_PAR_EL1]
	msr par_el1, x13
	msr far_el1, x14

	ldp x15, x16, [x0, #CTX_AFSR0_EL1]
	msr afsr0_el1, x15
	msr afsr1_el1, x16

	ldp x17, x9, [x0, #CTX_CONTEXTIDR_EL1]
	msr contextidr_el1, x17
	msr vbar_el1, x9

	/* Restore AArch32 system registers if the build has instructed so */
	#if CTX_INCLUDE_AARCH32_REGS
	ldp x11, x12, [x0, #CTX_SPSR_ABT]
	msr spsr_abt, x11
	msr spsr_und, x12

	ldp x13, x14, [x0, #CTX_SPSR_IRQ]
	msr spsr_irq, x13
	msr spsr_fiq, x14

	ldp x15, x16, [x0, #CTX_DACR32_EL2]
	msr dacr32_el2, x15
	msr ifsr32_el2, x16
	#endif /* CTX_INCLUDE_AARCH32_REGS */

	/* Restore NS timer registers if the build has instructed so */
	#if NS_TIMER_SWITCH
	ldp x10, x11, [x0, #CTX_CNTP_CTL_EL0]
	msr cntp_ctl_el0, x10
	msr cntp_cval_el0, x11

	ldp x12, x13, [x0, #CTX_CNTV_CTL_EL0]
	msr cntv_ctl_el0, x12
	msr cntv_cval_el0, x13

	ldr x14, [x0, #CTX_CNTKCTL_EL1]
	msr cntkctl_el1, x14
	#endif /* NS_TIMER_SWITCH */

	/* Restore MTE system registers if the build has instructed so */
	#if CTX_INCLUDE_MTE_REGS
	ldp x11, x12, [x0, #CTX_TFSRE0_EL1]
	msr TFSRE0_EL1, x11
	msr TFSR_EL1, x12

	ldp x13, x14, [x0, #CTX_RGSR_EL1]
	msr RGSR_EL1, x13
	msr GCR_EL1, x14
	#endif /* CTX_INCLUDE_MTE_REGS */

	/* No explict ISB required here as ERET covers it */
	ret
	endfunc el1_sysregs_context_restore

	/* ------------------------------------------------------------------
	* The following function follows the aapcs_64 strictly to use
	* x9-x17 (temporary caller-saved registers according to AArch64 PCS)
	* to save floating point register context. It assumes that 'x0' is
	* pointing to a 'fp_regs' structure where the register context will
	* be saved.
	*
	* Access to VFP registers will trap if CPTR_EL3.TFP is set.
	* However currently we don't use VFP registers nor set traps in
	* Trusted Firmware, and assume it's cleared.
	*
	* TODO: Revisit when VFP is used in secure world
	* ------------------------------------------------------------------
	*/
	#if CTX_INCLUDE_FPREGS
	func fpregs_context_save
	stp q0, q1, [x0, #CTX_FP_Q0]
	stp q2, q3, [x0, #CTX_FP_Q2]
	stp q4, q5, [x0, #CTX_FP_Q4]
	stp q6, q7, [x0, #CTX_FP_Q6]
	stp q8, q9, [x0, #CTX_FP_Q8]
	stp q10, q11, [x0, #CTX_FP_Q10]
	stp q12, q13, [x0, #CTX_FP_Q12]
	stp q14, q15, [x0, #CTX_FP_Q14]
	stp q16, q17, [x0, #CTX_FP_Q16]
	stp q18, q19, [x0, #CTX_FP_Q18]
	stp q20, q21, [x0, #CTX_FP_Q20]
	stp q22, q23, [x0, #CTX_FP_Q22]
	stp q24, q25, [x0, #CTX_FP_Q24]
	stp q26, q27, [x0, #CTX_FP_Q26]
	stp q28, q29, [x0, #CTX_FP_Q28]
	stp q30, q31, [x0, #CTX_FP_Q30]

	mrs x9, fpsr
	str x9, [x0, #CTX_FP_FPSR]

	mrs x10, fpcr
	str x10, [x0, #CTX_FP_FPCR]

	#if CTX_INCLUDE_AARCH32_REGS
	mrs x11, fpexc32_el2
	str x11, [x0, #CTX_FP_FPEXC32_EL2]
	#endif /* CTX_INCLUDE_AARCH32_REGS */
	ret
	endfunc fpregs_context_save

	/* ------------------------------------------------------------------
	* The following function follows the aapcs_64 strictly to use x9-x17
	* (temporary caller-saved registers according to AArch64 PCS) to
	* restore floating point register context. It assumes that 'x0' is
	* pointing to a 'fp_regs' structure from where the register context
	* will be restored.
	*
	* Access to VFP registers will trap if CPTR_EL3.TFP is set.
	* However currently we don't use VFP registers nor set traps in
	* Trusted Firmware, and assume it's cleared.
	*
	* TODO: Revisit when VFP is used in secure world
	* ------------------------------------------------------------------
	*/
	func fpregs_context_restore
	ldp q0, q1, [x0, #CTX_FP_Q0]
	ldp q2, q3, [x0, #CTX_FP_Q2]
	ldp q4, q5, [x0, #CTX_FP_Q4]
	ldp q6, q7, [x0, #CTX_FP_Q6]
	ldp q8, q9, [x0, #CTX_FP_Q8]
	ldp q10, q11, [x0, #CTX_FP_Q10]
	ldp q12, q13, [x0, #CTX_FP_Q12]
	ldp q14, q15, [x0, #CTX_FP_Q14]
	ldp q16, q17, [x0, #CTX_FP_Q16]
	ldp q18, q19, [x0, #CTX_FP_Q18]
	ldp q20, q21, [x0, #CTX_FP_Q20]
	ldp q22, q23, [x0, #CTX_FP_Q22]
	ldp q24, q25, [x0, #CTX_FP_Q24]
	ldp q26, q27, [x0, #CTX_FP_Q26]
	ldp q28, q29, [x0, #CTX_FP_Q28]
	ldp q30, q31, [x0, #CTX_FP_Q30]

	ldr x9, [x0, #CTX_FP_FPSR]
	msr fpsr, x9

	ldr x10, [x0, #CTX_FP_FPCR]
	msr fpcr, x10

	#if CTX_INCLUDE_AARCH32_REGS
	ldr x11, [x0, #CTX_FP_FPEXC32_EL2]
	msr fpexc32_el2, x11
	#endif /* CTX_INCLUDE_AARCH32_REGS */

	/*
	* No explict ISB required here as ERET to
	* switch to secure EL1 or non-secure world
	* covers it
	*/

	ret
	endfunc fpregs_context_restore
	#endif /* CTX_INCLUDE_FPREGS */

	/*
	* Set SCR_EL3.EA bit to enable SErrors at EL3
	*/
	.macro enable_serror_at_el3
	mrs x8, scr_el3
	orr x8, x8, #SCR_EA_BIT
	msr scr_el3, x8
	.endm

	/*
	* Set the PSTATE bits not set when the exception was taken as
	* described in the AArch64.TakeException() pseudocode function
	* in ARM DDI 0487F.c page J1-7635 to a default value.
	*/
	.macro set_unset_pstate_bits
	/*
	* If Data Independent Timing (DIT) functionality is implemented,
	* always enable DIT in EL3
	*/
	#if ENABLE_FEAT_DIT
	#if ENABLE_FEAT_DIT == 2
	mrs x8, id_aa64pfr0_el1
	and x8, x8, #(ID_AA64PFR0_DIT_MASK << ID_AA64PFR0_DIT_SHIFT)
	cbz x8, 1f
	#endif
	mov x8, #DIT_BIT
	msr DIT, x8
	1:
	#endif /* ENABLE_FEAT_DIT */
	.endm /* set_unset_pstate_bits */

	/*-------------------------------------------------------------------------
	* This macro checks the ENABLE_FEAT_MPAM state, performs ID register
	* check to see if the platform supports MPAM extension and restores MPAM3
	* register value if it is FEAT_STATE_ENABLED/FEAT_STATE_CHECKED.
	*
	* This is particularly more complicated because we can't check
	* if the platform supports MPAM by looking for status of a particular bit
	* in the MDCR_EL3 or CPTR_EL3 register like other extensions.
	* ------------------------------------------------------------------------
	*/

	.macro restore_mpam3_el3
	#if ENABLE_FEAT_MPAM
	#if ENABLE_FEAT_MPAM == 2

	mrs x8, id_aa64pfr0_el1
	lsr x8, x8, #(ID_AA64PFR0_MPAM_SHIFT)
	and x8, x8, #(ID_AA64PFR0_MPAM_MASK)
	mrs x7, id_aa64pfr1_el1
	lsr x7, x7, #(ID_AA64PFR1_MPAM_FRAC_SHIFT)
	and x7, x7, #(ID_AA64PFR1_MPAM_FRAC_MASK)
	orr x7, x7, x8
	cbz x7, no_mpam
	#endif
	/* -----------------------------------------------------------
	* Restore MPAM3_EL3 register as per context state
	* Currently we only enable MPAM for NS world and trap to EL3
	* for MPAM access in lower ELs of Secure and Realm world
	* x9 holds address of the per_world context
	* -----------------------------------------------------------
	*/

	ldr x17, [x9, #CTX_MPAM3_EL3]
	msr S3_6_C10_C5_0, x17 /* mpam3_el3 */

	no_mpam:
	#endif
	.endm /* restore_mpam3_el3 */

	/* ------------------------------------------------------------------
	* The following macro is used to save and restore all the general
	* purpose and ARMv8.3-PAuth (if enabled) registers.
	* It also checks if the Secure Cycle Counter (PMCCNTR_EL0)
	* is disabled in EL3/Secure (ARMv8.5-PMU), wherein PMCCNTR_EL0
	* needs not to be saved/restored during world switch.
	*
	* Ideally we would only save and restore the callee saved registers
	* when a world switch occurs but that type of implementation is more
	* complex. So currently we will always save and restore these
	* registers on entry and exit of EL3.
	* clobbers: x18
	* ------------------------------------------------------------------
	*/
	.macro save_gp_pmcr_pauth_regs
	stp x0, x1, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X0]
	stp x2, x3, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X2]
	stp x4, x5, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X4]
	stp x6, x7, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X6]
	stp x8, x9, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X8]
	stp x10, x11, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X10]
	stp x12, x13, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X12]
	stp x14, x15, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X14]
	stp x16, x17, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X16]
	stp x18, x19, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X18]
	stp x20, x21, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X20]
	stp x22, x23, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X22]
	stp x24, x25, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X24]
	stp x26, x27, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X26]
	stp x28, x29, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X28]
	mrs x18, sp_el0
	str x18, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_SP_EL0]

	/* PMUv3 is presumed to be always present */
	mrs x9, pmcr_el0
	str x9, [sp, #CTX_EL3STATE_OFFSET + CTX_PMCR_EL0]
	/* Disable cycle counter when event counting is prohibited */
	orr x9, x9, #PMCR_EL0_DP_BIT
	msr pmcr_el0, x9
	isb
	#if CTX_INCLUDE_PAUTH_REGS
	/* ----------------------------------------------------------
	* Save the ARMv8.3-PAuth keys as they are not banked
	* by exception level
	* ----------------------------------------------------------
	*/
	add x19, sp, #CTX_PAUTH_REGS_OFFSET

	mrs x20, APIAKeyLo_EL1 /* x21:x20 = APIAKey */
	mrs x21, APIAKeyHi_EL1
	mrs x22, APIBKeyLo_EL1 /* x23:x22 = APIBKey */
	mrs x23, APIBKeyHi_EL1
	mrs x24, APDAKeyLo_EL1 /* x25:x24 = APDAKey */
	mrs x25, APDAKeyHi_EL1
	mrs x26, APDBKeyLo_EL1 /* x27:x26 = APDBKey */
	mrs x27, APDBKeyHi_EL1
	mrs x28, APGAKeyLo_EL1 /* x29:x28 = APGAKey */
	mrs x29, APGAKeyHi_EL1

	stp x20, x21, [x19, #CTX_PACIAKEY_LO]
	stp x22, x23, [x19, #CTX_PACIBKEY_LO]
	stp x24, x25, [x19, #CTX_PACDAKEY_LO]
	stp x26, x27, [x19, #CTX_PACDBKEY_LO]
	stp x28, x29, [x19, #CTX_PACGAKEY_LO]
	#endif /* CTX_INCLUDE_PAUTH_REGS */
	.endm /* save_gp_pmcr_pauth_regs */

	/* -----------------------------------------------------------------
	* This function saves the context and sets the PSTATE to a known
	* state, preparing entry to el3.
	* Save all the general purpose and ARMv8.3-PAuth (if enabled)
	* registers.
	* Then set any of the PSTATE bits that are not set by hardware
	* according to the Aarch64.TakeException pseudocode in the Arm
	* Architecture Reference Manual to a default value for EL3.
	* clobbers: x17
	* -----------------------------------------------------------------
	*/
	func prepare_el3_entry
	save_gp_pmcr_pauth_regs
	enable_serror_at_el3
	/*
	* Set the PSTATE bits not described in the Aarch64.TakeException
	* pseudocode to their default values.
	*/
	set_unset_pstate_bits
	ret
	endfunc prepare_el3_entry

	/* ------------------------------------------------------------------
	* This function restores ARMv8.3-PAuth (if enabled) and all general
	* purpose registers except x30 from the CPU context.
	* x30 register must be explicitly restored by the caller.
	* ------------------------------------------------------------------
	*/
	func restore_gp_pmcr_pauth_regs
	#if CTX_INCLUDE_PAUTH_REGS
	/* Restore the ARMv8.3 PAuth keys */
	add x10, sp, #CTX_PAUTH_REGS_OFFSET

	ldp x0, x1, [x10, #CTX_PACIAKEY_LO] /* x1:x0 = APIAKey */
	ldp x2, x3, [x10, #CTX_PACIBKEY_LO] /* x3:x2 = APIBKey */
	ldp x4, x5, [x10, #CTX_PACDAKEY_LO] /* x5:x4 = APDAKey */
	ldp x6, x7, [x10, #CTX_PACDBKEY_LO] /* x7:x6 = APDBKey */
	ldp x8, x9, [x10, #CTX_PACGAKEY_LO] /* x9:x8 = APGAKey */

	msr APIAKeyLo_EL1, x0
	msr APIAKeyHi_EL1, x1
	msr APIBKeyLo_EL1, x2
	msr APIBKeyHi_EL1, x3
	msr APDAKeyLo_EL1, x4
	msr APDAKeyHi_EL1, x5
	msr APDBKeyLo_EL1, x6
	msr APDBKeyHi_EL1, x7
	msr APGAKeyLo_EL1, x8
	msr APGAKeyHi_EL1, x9
	#endif /* CTX_INCLUDE_PAUTH_REGS */

	/* PMUv3 is presumed to be always present */
	ldr x0, [sp, #CTX_EL3STATE_OFFSET + CTX_PMCR_EL0]
	msr pmcr_el0, x0
	ldp x0, x1, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X0]
	ldp x2, x3, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X2]
	ldp x4, x5, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X4]
	ldp x6, x7, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X6]
	ldp x8, x9, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X8]
	ldp x10, x11, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X10]
	ldp x12, x13, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X12]
	ldp x14, x15, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X14]
	ldp x16, x17, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X16]
	ldp x18, x19, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X18]
	ldp x20, x21, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X20]
	ldp x22, x23, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X22]
	ldp x24, x25, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X24]
	ldp x26, x27, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X26]
	ldr x28, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_SP_EL0]
	msr sp_el0, x28
	ldp x28, x29, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X28]
	ret
	endfunc restore_gp_pmcr_pauth_regs

	/*
	* In case of ERRATA_SPECULATIVE_AT, save SCTLR_EL1 and TCR_EL1
	* registers and update EL1 registers to disable stage1 and stage2
	* page table walk
	*/
	func save_and_update_ptw_el1_sys_regs
	/* ----------------------------------------------------------
	* Save only sctlr_el1 and tcr_el1 registers
	* ----------------------------------------------------------
	*/
	mrs x29, sctlr_el1
	str x29, [sp, #(CTX_EL1_SYSREGS_OFFSET + CTX_SCTLR_EL1)]
	mrs x29, tcr_el1
	str x29, [sp, #(CTX_EL1_SYSREGS_OFFSET + CTX_TCR_EL1)]

	/* ------------------------------------------------------------
	* Must follow below order in order to disable page table
	* walk for lower ELs (EL1 and EL0). First step ensures that
	* page table walk is disabled for stage1 and second step
	* ensures that page table walker should use TCR_EL1.EPDx
	* bits to perform address translation. ISB ensures that CPU
	* does these 2 steps in order.
	*
	* 1. Update TCR_EL1.EPDx bits to disable page table walk by
	* stage1.
	* 2. Enable MMU bit to avoid identity mapping via stage2
	* and force TCR_EL1.EPDx to be used by the page table
	* walker.
	* ------------------------------------------------------------
	*/
	orr x29, x29, #(TCR_EPD0_BIT)
	orr x29, x29, #(TCR_EPD1_BIT)
	msr tcr_el1, x29
	isb
	mrs x29, sctlr_el1
	orr x29, x29, #SCTLR_M_BIT
	msr sctlr_el1, x29
	isb

	ret
	endfunc save_and_update_ptw_el1_sys_regs

	/* -----------------------------------------------------------------
	* The below macro returns the address of the per_world context for
	* the security state, retrieved through "get_security_state" macro.
	* The per_world context address is returned in the register argument.
	* Clobbers: x9, x10
	* ------------------------------------------------------------------
	*/

	.macro get_per_world_context _reg:req
	ldr x10, [sp, #CTX_EL3STATE_OFFSET + CTX_SCR_EL3]
	get_security_state x9, x10
	mov_imm x10, (CTX_PERWORLD_EL3STATE_END - CTX_CPTR_EL3)
	mul x9, x9, x10
	adrp x10, per_world_context
	add x10, x10, :lo12:per_world_context
	add x9, x9, x10
	mov \_reg, x9
	.endm

	/* ------------------------------------------------------------------
	* This routine assumes that the SP_EL3 is pointing to a valid
	* context structure from where the gp regs and other special
	* registers can be retrieved.
	* ------------------------------------------------------------------
	*/
	func el3_exit
	#if ENABLE_ASSERTIONS
	/* el3_exit assumes SP_EL0 on entry */
	mrs x17, spsel
	cmp x17, #MODE_SP_EL0
	ASM_ASSERT(eq)
	#endif /* ENABLE_ASSERTIONS */

	/* ----------------------------------------------------------
	* Save the current SP_EL0 i.e. the EL3 runtime stack which
	* will be used for handling the next SMC.
	* Then switch to SP_EL3.
	* ----------------------------------------------------------
	*/
	mov x17, sp
	msr spsel, #MODE_SP_ELX
	str x17, [sp, #CTX_EL3STATE_OFFSET + CTX_RUNTIME_SP]

	/* ----------------------------------------------------------
	* Restore CPTR_EL3.
	* ZCR is only restored if SVE is supported and enabled.
	* Synchronization is required before zcr_el3 is addressed.
	* ----------------------------------------------------------
	*/

	/* The address of the per_world context is stored in x9 */
	get_per_world_context x9

	ldp x19, x20, [x9, #CTX_CPTR_EL3]
	msr cptr_el3, x19

	#if IMAGE_BL31
	ands x19, x19, #CPTR_EZ_BIT
	beq sve_not_enabled

	isb
	msr S3_6_C1_C2_0, x20 /* zcr_el3 */
	sve_not_enabled:

	restore_mpam3_el3

	#endif /* IMAGE_BL31 */

	#if IMAGE_BL31 && DYNAMIC_WORKAROUND_CVE_2018_3639
	/* ----------------------------------------------------------
	* Restore mitigation state as it was on entry to EL3
	* ----------------------------------------------------------
	*/
	ldr x17, [sp, #CTX_CVE_2018_3639_OFFSET + CTX_CVE_2018_3639_DISABLE]
	cbz x17, 1f
	blr x17
	1:
	#endif /* IMAGE_BL31 && DYNAMIC_WORKAROUND_CVE_2018_3639 */

	#if IMAGE_BL31
	synchronize_errors
	#endif /* IMAGE_BL31 */

	/* ----------------------------------------------------------
	* Restore SPSR_EL3, ELR_EL3 and SCR_EL3 prior to ERET
	* ----------------------------------------------------------
	*/
	ldr x18, [sp, #CTX_EL3STATE_OFFSET + CTX_SCR_EL3]
	ldp x16, x17, [sp, #CTX_EL3STATE_OFFSET + CTX_SPSR_EL3]
	msr scr_el3, x18
	msr spsr_el3, x16
	msr elr_el3, x17

	restore_ptw_el1_sys_regs

	/* ----------------------------------------------------------
	* Restore general purpose (including x30), PMCR_EL0 and
	* ARMv8.3-PAuth registers.
	* Exit EL3 via ERET to a lower exception level.
	* ----------------------------------------------------------
	*/
	bl restore_gp_pmcr_pauth_regs
	ldr x30, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_LR]

	#ifdef IMAGE_BL31
	/* Clear the EL3 flag as we are exiting el3 */
	str xzr, [sp, #CTX_EL3STATE_OFFSET + CTX_NESTED_EA_FLAG]
	#endif /* IMAGE_BL31 */

	exception_return

	endfunc el3_exit